1970 Fuel Pump problem?

[Chris Dransfield]

My 70 big block has started to consistently bog down under hard accelleration. It runs fine at cruising speed and idles fine. I thought perhaps it might be condensation in the tank but this tested negative with the water identification paste as mentioned in previous posts. The fuel filter was also just replaced.

I am now thinking of replacing the fuel pump. Is this perhaps a typical indication the fuel pump is going bad. The car also cranks for 6-7 seconds before starting after sitting for a day.There is some visible small rust particles in the tank from age.

Plugs changed and timing set with no difference.

Comments welcome.....

[Richard W.]

Re: 1970 Fuel Pump problem?

The fuel filter isn't in backwards is it? I have experienced this before (not by me!) and it causes these symptoms. Rick

[Chris Dransfield]

Re: 1970 Fuel Pump problem?

No fuel filter is in ok. Is there a way to check fuel pressure under heavy acceleration? Hate to spend $125 on correct NCRS fuel pump to find out it is not the problem.

[Zachary K.]

Re: 1970 Fuel Pump problem?

Chris, how old are the rubber hoses from the tank to the line and the line to the pump. Old hoses either could be soft and get sucked closed or could be starting to dry rot and will pull air through. Just a quick and inexpensive check!! You also have a filter (sock) on the tank sending unit pickup to check also.